The invention concerns a device for mounting and dismounting a bearing assembly of the roll neck of the backup roll of a rolling stand, wherein the bearing assembly comprises a chock and a roll neck bearing mounted in the chock.
It has long been known how to support backup rolls of rolling stands in bearing assemblies, e.g., Morgoil bearings. Nuts are still widely used for mounting the bearing assemblies on and dismounting them from the roll necks. The bearing assembly can be mechanically mounted on the journal with these nuts. To dismount the bearing assembly, after removal of the mechanical nuts, the bearing assembly is dismounted from the roll neck by means of levers, wedges, and the like or by ramming heavy weights, e.g., another roll, against the chocks.
However, it is also well known that the bearing assembly can be equipped with projections that enclose both flanks of the nut, so that when the nut is screwed on, the bearing assembly is mounted, and when the nut is unscrewed, the bearing assembly is dismounted. The large forces that this requires are often applied by winding a crane cable around the nut and loosening or tightening the nut by a lifting movement of the crane. This method of tightening or loosening the nut is extremely dangerous, since operating personnel can be injured if the tensioned crane cable slips.
Hydraulic mounting and dismounting devices built into the bearing assembly for mounting and dismounting the bearing assemblies of roll necks are also known, which always remain in each of the bearing assembles and can be coupled with external hydraulic sources to carry out the mounting or dismounting. However, these devices for mounting and dismounting the bearing assembles are complicated and expensive. Existing rolls that use only mechanical nuts for mounting and dismounting can be retrofitted with this type of mounting and dismounting device only with considerable, cost-intensive changes in the roll neck. Therefore, this type of retrofitting is not economically feasible.
In addition, hydraulic mounting and dismounting devices are known which can be temporarily coupled with the bearing assembly, but special designs of the journals are also necessary to allow them to be flange-mounted on the journals.
The replacement of the mechanical nut for the mounting of bearing assemblies by a hydraulic nut has also been proposed. However, after the hydraulic nut has been removed, here again it is necessary to remove the bearing assemblies from the roll neck by means of levers, wedges, the aforementioned ramming, etc.
The initially described mechanical nuts for mounting bearing assemblies on backup roll necks are still widely used. However, these nuts do not meet required safety standards with respect to mounting by crane and with respect to dismounting by levers, wedges, ramming, etc.